Apparatus for coating beveled edges



July 11, 1939. A. w. BALDWIN 7 2,155,210

APPARATUS FOR COATING BEVELED EDGES FiledDec. 16, 1936 xflFeso W .BALDW/M Patented July 11, 1939 UNITED STATES PATENT OFFICE APPARATUS FOR COATING BEVELED EDGES Application December 16, 1936, Serial No. 116,054

2 Claims.

This invention relates to apparatus for coating beveled edges, more particularly in connection with the manufacture of coated wall board.

In accordance with one method of improving the surface of wall board, with which this inven- 'tion is particularly concerned, both of the broad surfaces of the wall board are coated with a casein or starch emulsion or paint and the coating then dried, smoothed and hardened by the application of heat and pressure thereto through the medium of heated rolls, platens, or the like. Where the wall board is to be used to simulate tiles, and also in certain other instances, it is desirable to provide the board with beveled edges l 3 having the same surface characteristics, although perhaps of a different color, as are imparted to the broad surfaces of the board by the coating steps just described.

It is diflicult, however, to coat the beveled edges of the board and obtain a perfect coating on the beveled edges that will not overlap the coating on the broad plane face of the board or otherwise show objectionable characteristics. If, for instance, the coating is applied to the beveled edges 5 by means of fountain rolls, brushes, or the like,

there is likely to be some overlapping of the coatings giving rise to the formation of .a head or other noticeable marking that is objectionable.

In accordance with'the principles of this in-- so vention, the'beveled edges of wall board and the like can be readily coated to obtain a perfect match with the coated faces of the board without any overlapping of the coatings. The mode of operation of my apparatus briefly comprises transferring a film of the coating compositionfrom the plane surface of a revolving disk to the beveled edge surfaces-of the board. In order to insure the absence of overlap, the disk is set at a slight angle to the surface of the beveled edge, with the rim of the disk coincident with the lateral edge of a broad face'of the board. As the board is advanced past therevolving disk, the

pond of the coating composition that is formed in back of the line of contact between the plane face of the diskand the beveled edge of the board is constantly being rolled into the surface of the beveled edge of the board and any excess wiped away by the revolving plane face of the disk. The coated surface is then dried, smoothed and hardened by contact with a heated beveled disk or roller.

It is therefore an important object of this invention to provide an apparatus for coating beveled edges of wall board and the like with a composition that will improve the surface characteristics of the beveled edges .and at the same time match a similar coating previously applied to the broad faces of the wall board.

Other and further important objects of this invention will be apparent from the disclosures I in the specification and the accompanying drawmg.

This invention (in a preferred form) is illustrated in the drawing and hereinafter more fully described.

0n t e drawing:

Fig 1 is a front elevational view, partly in section, of coating apparatus embodying my invention.

-Figure 2 is an enlarged fragmentary view lookingsubstantially along the line IIII of Fig. 1.

Figure 3 is an enlarged fragmentary sectional view of the wall board with the coating disk in elevation.

Figure 4 is an elevational view looking toward the plane working face of the coating disk in a horizontal direction at right angles to the line of travel of the board, with the parts of the apparatus in section and with the board being coated removed. v I 25 Figure 5 is a front elevational view of the ironing'apparatus for drying, smoothing and hardening the coated beveled edge of the board, with the beveled disk of the apparatus in section.

' As shown on the drawing: 30

The reference numeral lliindicates a strip of wall board having a beveled, edge II that it is desired to coat. The board III is one that has already been coated on its surface l2 with a coating composition similar to that which is to be 35 applied to the beveled edge II in accordance with the apparatus and method of this invention.

As shown in Fig. 1, the edge coating apparatus I comprises a disk ll mounted on the lower end of 40 an inclined shaft ii that is 'journaled in bearings l6 and I1. Any suitable means, such as the pulley l8 and belt l9,- may be employed to rotate the disk It.

The lower portion of said disk ll dips slightly 5 beneath the surface of a bath 20 of a coating composition contained wtihin a receptacle 2| to pick up a ribbon-like film 38 (Fig. 4) of the coating composition on the plane face 24. A wiper 22 mounted just above the level of the bath 20, bears against the upwardly moving cylindrical edge surface l3 of the disk I4 to wipe the same free of the coating composition so that none of the composition can run downwardlyfrom this edge onto the surface of the board 10 to form a I I head or overlapping of coatings at the edge 23 (Fig. 3). Said wiper 22 may be in the form of a 7 blade or scraper of leather, steel -or other suitable material. v

A second wiper 36 (Fig. 4-), preferably of metal, is arranged to remove any remaining coating composition, such as indicated by the film 31, from the plane face 24 of the disk. The coating composition so removed by said wipers 22 and 36 runs back into the container 2|. The strip of wall board I8 is advanced past the coating disk H in a straight linear movement. Any suitable means (not shown) may be employed for supporting and advancing the board Ill. The disk 14 is so mounted that its plane face 24 forms a slight angle, indicated at X (Fig. "2), with the plane of the bevel H. 'The purpose of providing this angular relationship is to permit the ribbon-like film 38 of coating composition, picked up by the plane surface 24, to build up into a pond 25, from which the composition is rolled onto thebevel ll. It is furthermore apparent that if the plane surface 24 were not setat an This arrangement insures a thorough, even coating of the surface of the bevel ll.

The wedge-shaped fillet or pond 25 of the coating composition builds up in back of the line of contact between the disk edge 26 and the surface of the bevel l I; and from this pond, the coating composition is rolled on to the surface. of the bevel II in a uniform manner. The disk I4 is preferably rotated at the same surface speed as that of the board l0, although a slight variation in speeds is permissible. If the disk is rotated at a surface speed greater than that of the board, the quantity of coatingj-composition applied to the bevel II will be increased. Practically, how- I r The reference numeral 39 (Fig. 4) indicates. the point at which a ribbon the width of the edge 7 II of the coating composition; has been transferred from the plane surface 24 'of the disk l4 to the, beveled edge II. The remaining ribbon 31 of the coating composition is removed by the 1 ever, it is best to control the amount of'the composition applied by regulating the density, or

thickness, of the coating composition.

8 wiper 38, above described, before that portion of the disk again dips into the bath 20. If the film '3] were not completely removed to present a fresh, clean surface for receiving a'new film 38 of the coating composition; the inactive film 81 would build up toa point where it would give difliculty by coming into contact with the lower projecting lip 48 (Fig. 1) on the female edge of theboard. It would also destroy the uniformity After leaving the coatingstation, theboard 18 is advanced to bring the coated bevel ll into contact were heated disk or roller 28. The roller 28 may suitably comprises. shell having a smooth,

polished conical or beveled face 28 se'tat'thesame angle as the bevel ll of the board. The

roller 28 is mounted upon a shaft 38 journaled in bearings iiand 82 and driven through a pulley may be added,

' is no overlapping of 33 and belt 34, or by othersuitable means. Said roller 28 may be heated by means of a gas fiame 35 directed against its inner face. As is obvious, other suitable means may be employed for maintaining the roller 28 at the desired temperature,

which is anywhere above the boiling point of water up to, say, 700 F., in the case of aqueous coating compositions.

The roller 28 is revolved at such a rate that the peripheral speed of the beveled face 29 is substantially the same as the linear speed of travel of the board l0, so that there is no appreciable relative surface movement between the contacting beveled surfaces. The action of the roller 28 is to dry the aqueous coating composition applied to the bevel II and to smooth and harden the same.

Various coating compositions may be employed with my method and apparatus, but my invention particularly contemplates the use of aqueous solutions or emulsions of binding agents, such as casein, starch, and vegetable and animal albumins, or mixtures of-any two or more of these agents. Wetting agents, such as pine oil, sulfates of high molecular weight alcohols, alkali metal sulfonates of alkylated naphthalene, or the like, are advantageously used, particularly where the board has been formed from pulp prepared from solvent extracted southern pine chips. In

that case, because of the water resistance of the resin impregnated and sized fibers, the wetting agents are of assistance in efiecting'a penetration of the coating composition into the surface fibers of the board, thereby securing a firm bonding of the coating to the fibers.

Various fillers, such as China clay, mica, or other siliceous or argillaceous materials, and pigments, such as lithophone, zinc oxide, whiting, titanium dioxide and the like, may be incorporated into the coating composition. Likewise, hardening and waterproofing agents, such as drying oils, rosins, waxes, formaldehyde, and others may be used to increase the hardness and waterproofness of the coating. Where ine oil is used as the wetting agent, it also serves as a preservative, but other preservatives, fungicides and the like as desired, to the coating composition. V I

For the most advantageous use of my present invention, the same coating composition is used in coating the beveled edges of the wall board as is used in the previous steps of coating the broad surfaces of the board- The broad surfaces of the board are coated before the board is cut up into been cut to the desired size for planks, tiles or the like, and the edges have been beveled and grooved, the planks or tiles are then coated along their beveled edges in the manner already described. By following this procedure, an'exact registration of the coatings on thebevel and on the broad face of the board adjacent the common edge23 is possible. Wherethe coatings are colored, the colors may be perfectly matched, if

desired, or a differently colored paint may be applied tothe beveled edge from that applied.- to the broad surface of the board. In either case there the coatings at the-common edge 23.

I am aware that many changes maybe'made do not purpose limiting the patent granted hereon otherwise than necessitated by the prior art.

I claim as my invention:

1. Apparatus for coating plane edge surfaces, comprising a rotatable disk having a circular plane face inclined at an angle to the horizontal, a supply of a coating composition into which the lower edge of said plane face dips and means for revolving said disk to transfer a film of said coating composition to a plane edge surface to be.

coated, said plane face being arranged at a slight angle to the surface of said plane edge to form line contact therewith, whereby a wedgeshaped fillet of said coating composition is built up in back of said line contact.

2. Apparatus for coating plane edge surfaces, comprising a rotatable member having a lower circular plane face inclined at an angle to the horizontal, a supply of a coating composition into which the lower edge of said plane face dips and means for revolving said disk to transfer a film of said coating composition from said lower ALFRED W. BALDWIN. 

